From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754052AbYLIQZ2 (ORCPT ); Tue, 9 Dec 2008 11:25:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753188AbYLIQZQ (ORCPT ); Tue, 9 Dec 2008 11:25:16 -0500 Received: from tomts22.bellnexxia.net ([209.226.175.184]:59433 "EHLO tomts22-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753041AbYLIQZO (ORCPT ); Tue, 9 Dec 2008 11:25:14 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Au4EADkqPklMROB9/2dsb2JhbACBbM9Ugwc Date: Tue, 9 Dec 2008 11:25:12 -0500 From: Mathieu Desnoyers To: Tom Zanussi Cc: Lai Jiangshan , linux-kernel@vger.kernel.org Subject: [PATCH] Relay : fix cpu offline problem Message-ID: <20081209162512.GB24039@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 11:23:30 up 22 days, 17:03, 3 users, load average: 0.94, 0.88, 0.76 User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Here is a fix for how relay handles cpu hotplug in the allocation error path. If a cpu goes down while allocating, it may result in a buffer never being freed. Lai Jiangshan originally identified this problem in the LTTng fork of relay (ltt-relay-alloc). Here is the fix which applies to the original kernel/relay.c. Signed-off-by: Mathieu Desnoyers CC: Lai Jiangshan CC: Tom Zanussi --- kernel/relay.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) Index: linux-2.6-lttng/kernel/relay.c =================================================================== --- linux-2.6-lttng.orig/kernel/relay.c 2008-12-09 10:58:45.000000000 -0500 +++ linux-2.6-lttng/kernel/relay.c 2008-12-09 11:09:58.000000000 -0500 @@ -611,10 +611,9 @@ struct rchan *relay_open(const char *bas return chan; free_bufs: - for_each_online_cpu(i) { - if (!chan->buf[i]) - break; - relay_close_buf(chan->buf[i]); + for_each_possible_cpu(i) { + if (chan->buf[i]) + relay_close_buf(chan->buf[i]); } kref_put(&chan->kref, relay_destroy_channel); -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68